The present invention relates generally to a container for shipping and storing temperature-sensitive products, and in particular to a container for maintaining frozen tissues and other products during shipping and storage.
Currently available containers for transporting frozen or refrigerated products generally include a cardboard shipping carton lined with insulating material such as such as expanded polystyrene (EPS), polyurethane or other foam material. The insulating material may be in the shape of modular panels or, for example, may be injection molded into any desired shape. The insulation typically defines a central cavity where products are stored along with a coolant, such as ice packs or loose blocks of dry ice. A plug, such as a thick polyester or polyether foam pad, is generally placed over the top of the product before the carton is closed and prepared for shipping.
Such conventional shipping containers have many limitations, particularly when shipping or storing sensitive frozen products, such as sterile frozen tissue samples, for extended periods of time. For example, engineered tissue implants, must be maintained in a sterile condition at or below approximately xe2x88x9265xc2x0 C. for a number of days during transcontinental or international shipping, particularly in the case of shipping delays or extended storage. Conventional containers simply are not adequately insulated or designed to maintain such products at low temperatures for more than one or two days. While increasing the thickness and/or number of layers of insulating material may aid in extending product maintenance time, the resulting increase in size and cost of such a shipping container is typically prohibitive.
Another problem with conventional shipping containers is that they fail to provide constant, evenly distributed contact between coolant and product. Such constant contact and even distribution of the coolant is desirable for maintaining frozen products over an extended period of time. In typical shipping containers, however, products and/or coolant blocks often shift during shipping and handling, resulting in a loss of contact or a change in the distribution of coolant. Such shifting is increasingly problematic during extended periods when the coolant decreases in size as it melts or sublimates, or if a recipient removes a portion of the product and wishes to maintain the rest in the container. Shifting of contents during transport may also result in damage to the product, its packaging or labeling, and may compromise product sterility. Additionally, in situations where a coolant block is placed on top of a product, conventional containers require a recipient to handle the block to access the product, possibly resulting in injury to the recipient or damage to the product.
Accordingly, there remains a need in the art for a improved container for shipping and storing varying amounts of frozen products at low temperatures for extended periods of time, while minimizing overall size and weight of the container.
The present invention is directed to a container for shipping and storing frozen products. In particular the present invention is directed to an insulated container for shipping and storing frozen tissue samples for an extended period of time. An exemplary embodiment of the container of the present invention includes a body having an open end and a product chamber, a spring assembly inside of the product chamber for supporting a cooling block and one or more packages of tissue (e.g. engineered tissue samples), and a lid assembly including one or more cooling blocks suspended therefrom that contact at least one of the tissue packages when the lid assembly is placed over the open end of the container body. The body of the container is dimensioned to fit within an outer container for shipping.
In the above-described exemplary embodiment, the body of the container includes an inner container and an outer container. The outer container is in the shape of an open box, with four side walls and a bottom lid of insulated foam material, such as EPS, polyurethane or any other rigid or soft foam. The inner surface of the walls and bottom of the outer container are lined with four vacuum insulated side panels and a bottom panel that comprise the inner container and define the product chamber. In certain embodiments, the outer and/or inner container have more than four walls, such that the body and/or product chamber is hexagonal, octagonal or the like. In certain other embodiments, the outer and/or inner containers may have less than four walls, such that the body and/or product chamber is triangular, cylindrical, elliptical, etc.
In an exemplary embodiment, a gasket is disposed between the bottom edge of the side panels and the bottom panel to reduce air flow in or out of the chamber. Adjacent side panel are beveled to ensure a tight seal. Optionally, panels may be configured, attached or sealed in any manner to minimize leaks between adjacent panels. Optionally, the product chamber is lined with a single or double layer of corrugated cardboard or similar material to protect the vacuum panels.
The spring assembly of this exemplary embodiment fits in the bottom of the product chamber and has a resilient spring member disposed between two plates, a bottom plate and a top plate. The bottom plate rests against, and is optionally attached to, the bottom of the product chamber. The top plate faces the open end of the chamber, and is adapted to support the lower cooling block and the stack of tissue samples. A clip is added to the top plate to maintain the coolant on the center of the product. The clip anchors and positions the coolant on the center/main mass of the product and prevents the coolant from shifting, particularly when the shipper is laid on its side. When the lid assembly is placed over the body, the stack of tissue samples is held between the upper and lower cooling blocks by the force of the spring. The spring has enough travel to assure forceful contact regardless of the quantity of product being shipped and to allow for sublimation of the dry ice during shipping and storage. In an alternative embodiment, the spring assembly is positioned above the product, for example it may be attached to the lid assembly.
The lid assembly of the above-described exemplary embodiment includes a top lid, a top vacuum panel, and a restraint for suspending the upper cooling block(s). When placed over the body, the restraint is disposed within the product chamber, the top panel mates with the inner chamber, and the top lid mates with the outer chamber. The elements of the lid assembly are attached for ease of removal, such that a recipient of the container need not touch the cooling blocks to access the tissue samples. A strap is optionally provided to aid in the removal of the lid assembly.